RESUMO
Polyphenolic compounds, such as resveratrol, have recently received widespread interest because of their ability to mimic effects of calorie restriction. The objective of the present study was to gain more insight into the effects of 30 days resveratrol supplementation on adipose tissue morphology and underlying processes. Eleven healthy obese men were supplemented with placebo and resveratrol for 30 days (150 mg per day), separated by a 4-week washout period in a double-blind randomized crossover design. A postprandial abdominal subcutaneous adipose tissue biopsy was collected to assess adipose tissue morphology and gene expression using microarray analysis. Resveratrol significantly decreased adipocyte size, with a shift toward a reduction in the proportion of large and very-large adipocytes and an increase in small adipocytes. Microarray analysis revealed downregulation of Wnt and Notch signaling pathways and upregulation of pathways involved in cell cycle regulation after resveratrol supplementation, suggesting enhanced adipogenesis. Furthermore, lysosomal/phagosomal pathway and transcription factor EB were upregulated reflecting an alternative pathway of lipid breakdown by autophagy. Further research is necessary to investigate whether resveratrol improves adipose tissue function.
Assuntos
Adipócitos/efeitos dos fármacos , Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Inibidores Enzimáticos/uso terapêutico , Obesidade/tratamento farmacológico , Estilbenos/uso terapêutico , Adipogenia/efeitos dos fármacos , Tecido Adiposo/efeitos dos fármacos , Adulto , Idoso , Estudos Cross-Over , Método Duplo-Cego , Perfilação da Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Obesidade/genética , Obesidade/metabolismo , Receptores Notch/efeitos dos fármacos , Receptores Notch/metabolismo , Resveratrol , Transdução de Sinais/efeitos dos fármacos , Resultado do Tratamento , Via de Sinalização Wnt/efeitos dos fármacosRESUMO
AIMS: Resveratrol, a natural polyphenolic compound produced by various plants (e.g. red grapes) and found in red wine, has glucose-lowering effects in humans and rodent models of obesity and/or diabetes. The mechanisms behind these effects have been suggested to include resveratrol-induced secretion of the gut incretin hormone glucagon-like peptide-1. We investigated postprandial incretin hormone and glucagon responses in obese human subjects before and after 30 days of resveratrol supplementation. METHODS: Postprandial plasma responses of the incretin hormones glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide and glucagon were evaluated in 10 obese men [subjects characteristics (mean ± standard error of the mean): age 52 ± 2 years; BMI 32 ± 1 kg/m(2), fasting plasma glucose 5.5 ± 0.1 mmol/l] who had been given a dietary supplement of resveratrol (Resvida(®) 150 mg/day) or placebo for 30 days in a randomized, double-blind, crossover design with a 4-week washout period. At the end of each intervention period a standardized meal test (without co-administration of resveratrol) was performed. RESULTS: Resveratrol supplementation had no impact on fasting plasma concentrations or postprandial plasma responses (area under curve values) of glucose-dependent insulinotropic polypeptide (11.2 ± 2.1 vs. 11.8 ± 2.2 pmol/l, P = 0.87; 17.0 ± 2.2 vs. 14.8 ± 1.6 min × nmol/l, P = 0.20) or glucagon-like peptide-1 (15.4 ± 1.0 vs. 15.2 ± 0.9 pmol/l, P = 0.84; 5.6 ± 0.4 vs. 5.7 ± 0.3 min × nmol/l, P = 0.73). Resveratrol supplementation significantly suppressed postprandial glucagon responses (4.4 ± 0.4 vs. 3.9 ± 0.4 min × nmol/l, P = 0.01) without affecting fasting glucagon levels (15.2 ± 2.2 vs. 14.5 ± 1.5 pmol/l, P = 0.56). CONCLUSIONS: Our data suggest that 30 days of resveratrol supplementation does not affect fasting or postprandial incretin hormone plasma levels in obese humans, but suppresses postprandial glucagon responses.
Assuntos
Antioxidantes/uso terapêutico , Glicemia/efeitos dos fármacos , Glucagon/efeitos dos fármacos , Obesidade/sangue , Estilbenos/uso terapêutico , Glicemia/metabolismo , Estudos Cross-Over , Suplementos Nutricionais , Método Duplo-Cego , Jejum , Polipeptídeo Inibidor Gástrico/sangue , Polipeptídeo Inibidor Gástrico/efeitos dos fármacos , Glucagon/sangue , Peptídeo 1 Semelhante ao Glucagon/sangue , Peptídeo 1 Semelhante ao Glucagon/efeitos dos fármacos , Humanos , Incretinas/sangue , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Obesidade/tratamento farmacológico , Período Pós-Prandial , Resveratrol , Fatores de Tempo , Resultado do TratamentoRESUMO
OBJECTIVE: To validate the World Health Organization/Global Programme on AIDS (GPA) protocol for measuring HIV/sexually transmitted disease prevention indicators pertaining to knowledge and sexual practices of the general population. METHODS: Data were collected in Uganda during 1993. Three different interview strategies were complemented with qualitative methods, including observations at visits and key-informant interviews. Two interview strategies consisted of structured questionnaires which were applied to 460 randomly selected people aged 15-49 years and 60 intentionally selected women who were known prostitutes. The third strategy involved in-depth interviewing and was applied to a random subset of all respondents (n = 75). RESULTS: The three interview strategies generated similar results for demographic characteristics. The strategies using structured questionnaires gave similar results with regards to the number of reported sex partners and the prevalence of condom use, but differed from in-depth interviews on these aspects. The high numbers of casual sex partners of female prostitutes was confirmed by in-depth interviews but not via the questionnaires. CONCLUSION: The GPA questionnaire may not be optimal to capture people at high risk and to assess sexual behaviour, especially of people at high risk. Nevertheless, the questionnaire provides the most realistic option, since in-depth interviews are expensive and not as objective in assessing trends over time. Evaluation studies of HIV interventions in the general population should therefore be complemented with small qualitative studies to detect and iron out biases in interpreting results.
Assuntos
Coleta de Dados , Infecções por HIV/prevenção & controle , Vigilância da População , Comportamento Sexual , Infecções Sexualmente Transmissíveis/prevenção & controle , Adolescente , Adulto , Preservativos/estatística & dados numéricos , Feminino , Infecções por HIV/psicologia , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Trabalho Sexual , Parceiros Sexuais , Infecções Sexualmente Transmissíveis/psicologia , Inquéritos e Questionários , Uganda , Organização Mundial da SaúdeRESUMO
OBJECTIVE: Little is known about variations in patterns of sexual behaviour in different countries, cultures, and subpopulations that determine the spread of HIV-1. Quantitative studies are required to improve understanding. METHODS: To assess reported patterns of sexual behaviour, we administered a standardized questionnaire to 416 men and 498 women aged 15-49 years from a rural population in northwest Tanzania. RESULTS: Reported levels of sexual activity were highest in men and among younger age groups. The number of sexual partners and number of sex acts per unit of time were strongly correlated: men reported 10 times as many lifetime partners than women. Frequency of sexual partner exchange plateaued earlier in women (by age 25 years) than in men (by age 35 years). For the great majority, age of first intercourse was 15 years or younger; older subjects were older at first intercourse and had fewer lifetime partners than younger subjects. CONCLUSIONS: This age-related pattern suggests that more recent birth cohorts have behaviour patterns that increase the risk of sexually transmitted infectious agents such as HIV. Preventive education programmes should be targeted at young adults, who adopt higher risk profiles of frequent partner exchange linked with first intercourse at an early age.
Assuntos
Comportamento Sexual/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Coito , Feminino , Inquéritos Epidemiológicos , Humanos , Masculino , Pessoa de Meia-Idade , População Rural/estatística & dados numéricos , Fatores Sexuais , Parceiros Sexuais , Tanzânia/epidemiologiaRESUMO
BACKGROUND: Determining folate intake is difficult because existing folate data in food-composition tables are scarce and unreliable. OBJECTIVE: The purposes of this study were first to analyze 125 of the most important foods that contribute to folate intake in the Netherlands and second to estimate the folate intake of a representative sample of the population. DESIGN: We analyzed the folate content of foods by using a newly developed HPLC trienzyme method combined with an affinity chromatography cleanup step. These results were then used to estimate the folate intake of persons aged 1-92 y who participated in the second Dutch National Food Consumption Survey (DNFCS) in 1992 (n = 6218). RESULTS: For 35 important folate-containing foods, the mean relative folate contents measured by HPLC were 66%, 80%, and 77% of values for comparable foods included in the British food-composition table; the Ministry of Agriculture, Fisheries and Food table; and the US Department of Agriculture database, respectively. P values for comparison of relative values with 100% were 0.001, 0.171, and 0.144, respectively. The mean dietary folate intake of the DNFCS participants was 182 +/- 119 microg/d. Intake of supplement users (n = 86) was 344 microg/d, with 147 microg/d from supplements. On the basis of these findings, 42% of men and 54% of women do not meet current Dutch recommendations of 60 microg/d for children and 200 microg/d for adults. CONCLUSIONS: Total folate quantities in foods, analyzed by HPLC, are approximately 25% lower than amounts listed in recent food-composition tables estimated by use of the microbiological method. On the basis of these new data, approximately 50% of a representative Dutch population sample does not meet the current recommendations for folate intake.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Ácido Fólico/administração & dosagem , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Disponibilidade Biológica , Criança , Pré-Escolar , Cromatografia de Afinidade , Cromatografia Líquida de Alta Pressão/normas , Registros de Dieta , Suplementos Nutricionais , Feminino , Ácido Fólico/farmacocinética , Análise de Alimentos , Manipulação de Alimentos , Humanos , Lactente , Masculino , Pessoa de Meia-Idade , Países Baixos , Inquéritos Nutricionais , Valor Nutritivo , Controle de Qualidade , Estações do AnoRESUMO
A population-based HIV-1 seroprevalence survey of 4,086 individuals, aged 15-49 years, in the North Mara district of Tanzania from rural, periurban, and urban areas, including high-risk (prostitutes, and co-workers) individuals, was performed in 1989 and 1990. The overall seroprevalence was 7.3% (95% confidence interval, 6.5-8.1), with a gradient of seropositivity from high-risk 13.0% (9.1, 16.8), urban 8.8% (7.6, 10.0), periurban 6.5% (4.7, 8.4), to rural 2.6% (1.6, 3.7) subjects. Adjusted for population group, HIV-1 seroprevalence was significantly elevated for men over age 24 and for women 20-34 years old, while age-specific prevalence rates were similar for men and women in the rural area. Recent treponemal infection, measured by the rapid plasma reagin test, was not associated with HIV-1 seropositivity in men or women. These data suggest a growing HIV-1 epidemic paralleling rising rates in other rural areas of Africa distant from areas that have been previously recognized as having high prevalence.
Assuntos
Infecções por HIV/epidemiologia , Soroprevalência de HIV , HIV-1/imunologia , Adolescente , Adulto , Fatores Etários , Intervalos de Confiança , Feminino , Anticorpos Anti-HIV/sangue , Infecções por HIV/complicações , Humanos , Masculino , Pessoa de Meia-Idade , Razão de Chances , Prevalência , Fatores de Risco , População Rural , Fatores Sexuais , Sífilis/complicações , Sífilis/epidemiologia , Sorodiagnóstico da Sífilis , Tanzânia/epidemiologia , População UrbanaRESUMO
OBJECTIVE: To explore the proportion and characteristics of adolescents who use illicit drugs and contrast them with adolescents who do not use such drugs in Switzerland. To facilitate the detection of adolescents with drug related difficulties. METHODS: We used data from a national survey on adolescent health in Switzerland (N = 9,273) conducted in 1992 and 1993. The survey is based on self-administered questionnaires among a representative sample of adolescents enrolled in schools and apprenticeship programs. We used exploratory analysis for identifying characteristics which set the drug user apart from non-users and performed confirmatory multivariate logistic regression analysis to examine which variables remain independently associated with heroin or cocaine use. RESULTS: In Switzerland, 3.1% of adolescents have taken heroin or cocaine at least once in their life, and 27.7% have already used cannabis. Analysis of lifestyles and health of adolescents show that young drug users present difficulties in integrating in society, have health problems and difficulties in relationships, situations which tend to be less common among other adolescents. Yet, they also display marked similarities, most notably in that over 70% had seen a physician in the past year. However, while 40% of the drug users expressed a need for help with drug related problems, only 6% had actually talked about them with a physician. Characteristics that remained independently associated with heroin and cocaine use after controlling for confounding factors were age, sex, nationality, type of education, feelings of suicide, past and present smoking, and use of cannabis. CONCLUSION: The level of illicit drug use among Swiss adolescents is high compared to other European countries but lower than the United States. Drug-using adolescents display a constellation of characteristics which should make it possible to identify them and offer help. Yet, even though they may have frequent contact with the health services, their drug problems are generally not recognized by the gatekeepers of the health services and no specific aid is available to them. Drug prevention must be intensified and medical doctors sensitized to the drug problems which adolescents may face.
Assuntos
Comportamento do Adolescente , Drogas Ilícitas , Transtornos Relacionados ao Uso de Substâncias/epidemiologia , Adolescente , Adulto , Cannabis , Cocaína , Feminino , Nível de Saúde , Inquéritos Epidemiológicos , Heroína , Humanos , Modelos Logísticos , Masculino , Análise Multivariada , Aceitação pelo Paciente de Cuidados de Saúde/estatística & dados numéricos , Fatores de Risco , Assunção de Riscos , Transtornos Relacionados ao Uso de Substâncias/psicologia , Suíça/epidemiologiaRESUMO
At the end of April 2002, the Swedish Food Administration reported the presence of acrylamide in heat treated food products. Acrylamide has been shown to be toxic and carcinogenic in animals, and has been classified by the WHO/IARC among others as 'probably carcinogenic for humans'. The purposes of this study were firstly to analyse acrylamide contents of the most important foods contributing to such exposure, secondly, to estimate the acrylamide exposure in a representative sample of the Dutch population, and thirdly to estimate the public health risks of this consumption. We analysed the acrylamide content of foods with an LC-MS-MS method. The results were then used to estimate the acrylamide exposure of consumers who participated in the National Food Consumption Survey (NFCS) in 1998 (n=6250). The exposure was estimated using the probabilistic approach for the total Dutch population and several age groups. For 344 food products, acrylamide amounts ranged from <30 to 3100 microg/kg. Foods with the highest mean acrylamide amounts were potato crisps (1249 microg/kg), chips (deep-fried) (351 microg/kg), cocktail snacks (1060 microg/kg), and gingerbread (890 microg/kg). The mean acrylamide exposure of the NFCS participants was 0.48 microg/kg bw/day. Risk of neurotoxicity is negligible. From exposure estimations it appears that the additional cancer risk might not be negligible.
Assuntos
Acrilamidas/efeitos adversos , Acrilamidas/análise , Dieta , Análise de Alimentos , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Carcinógenos/toxicidade , Criança , Pré-Escolar , Cromatografia Líquida , Coleta de Dados , Feminino , Saúde , Humanos , Lactente , Masculino , Espectrometria de Massas , Pessoa de Meia-Idade , Países Baixos , Controle de Qualidade , Medição de RiscoRESUMO
A liquid chromatographic (LC) method was elaborated for determining folates in foods. Folates were extracted by homogenizing in buffer and heat treatment. A portion was incubated with an enzyme preparation containing conjugase, amylase, and protease. After purification by affinity chromatography, folate monoglutamates were determined by reversed-phase LC with fluorescence and diode array detection. Gradient elution with phosphate buffer and acetonitrile was used to separate vitamers. The most abundant folate forms naturally present in foods were detected, including tetrahydrofolic acid, 5-methyltetrahydrofolic acid, and 5-formyltetrahydrofolic acid. 10-Formylfolic acid could be detected by applying a second fluorescence detector. Folic acid, used for fortification, might also be quantitated with this system. The difference between folate concentrations in sample extracts, with and without treatment of conjugase, is a measure of the quantity of polyglutamates in the food matrixes. An additional treatment with conjugase, amylase, and protease reflects the amount of matrix-bound folates. The LC system gave a linear response over the range 0-100 ng/mL. Detection limit for these compounds were 7 pg/mL for tetrahydrofolic acid and 5-methyltetrahydrofolic acid and 59 pg/mL for 10-formylfolic acid (signal-to-noise ratio > or = 3) when 100 microL was injected. Detection limits for 5-formyltetrahydrofolic acid and folic acid were 1 ng/mL. Repeatability relative standard deviation values for separate folates in 3 candidate Certified Reference Materials (CRMs)--mixed vegetables (CRM 485), pig liver (CRM 487), and whole-meal flour (CRM 121)--and a Certified Reference Material milk powder (CRM 421) varied from 3.3 to 21.0% for the concentration range 1.8-1440 micrograms/100 g. Recoveries ranged from 73 to 109%. Use of amylase and protease was advantageous. Use of a commercially available folate-binding protein for cleanup saved time and money and was effective. Results for 5-methyltetrahydrofolic acid were in good agreement with results obtained with other LC methods. Results for total folates were lower than results obtained with microbiological methods.
Assuntos
Cromatografia Líquida/métodos , Ácido Fólico/análise , Análise de Alimentos , Animais , Cromatografia de Afinidade , Farinha/análise , Fígado/química , Leite/química , Reprodutibilidade dos Testes , Espectrometria de Fluorescência , Suínos , Verduras/químicaRESUMO
A liquid chromatographic (LC) method was developed for determination of tocopherols and tocotrienols in foods. Tocopherols and tocotrienols were released after saponification of test portions for 40 min at 80 degrees C, followed by extraction with hexane-ethyl acetate. After evaporation of the organic solvents, the extract was injected in the LC system. Separation of individual tocopherols and tocotrienols was satisfactory. Some interferences were encountered from tocomoneols, tocodienols, 2-tert-butyl-4-hydroxyanisole (BHA), 2,6-di-tert-butyl-4-methylphenol, (BHT), and plastochromanol-8. The response of the LC system was linear over a range of 0-10 micrograms/mL for tocopherols and tocotrienols. The detection limit for these compounds was 0.1 micrograms/mL. Repeatabilty relative standard deviation values for tocopherols and tocotrienols in margarine, infant formula, and broccoli (concentration range, 0.11-22 mg/100 g) varied from 1.3 to 6.4%. Recoveries ranged from 91 to 105%.
Assuntos
Antioxidantes/análise , Análise de Alimentos , Alimentos Infantis/análise , Margarina/análise , Verduras/química , Vitamina E/análise , Antioxidantes/metabolismo , Cromanos/análise , Cromanos/metabolismo , Cromatografia Líquida , Aditivos Alimentares , Liofilização , Humanos , Recém-Nascido , Reprodutibilidade dos Testes , Tocotrienóis , Vitamina E/análogos & derivados , Vitamina E/metabolismoRESUMO
Food supplements can contain polycyclic aromatic hydrocarbons (PAH). The European Food Safety Authority (EFSA) has defined 16 priority PAH that are both genotoxic and carcinogenic and identified eight priority PAH (PAH8) or four of these (PAH4) as good indicators of the toxicity and occurrence of PAH in food. The current study aimed to determine benzo[a]pyrene and other EFSA priority PAH in different categories of food supplements containing botanicals and other ingredients. From 2003 to 2008, benzo[a]pyrene exceeded the limit of quantification (LOQ) in 553 (44%) of 1258 supplements with a lower-bound mean of 3.37 µg kg(-1). In 2008 and 2009, benzo[a]pyrene and 12 other EFSA priority PAH were determined in 333 food supplements. Benzo[a]pyrene exceeded the LOQ in 210 (63%) food supplements with a lower-bound mean of 5.26 µg kg(-1). Lower-bound mean levels for PAH4 and PAH8(-indeno[1,2,3-cd]pyrene) were 33.5 and 40.5 µg kg(-1), respectively. Supplements containing resveratrol, Ginkgo biloba, St. John's wort and propolis showed relatively high PAH4 levels in 2008 and 2009. Before 2008, supplements with these ingredients and also dong quai, green tea or valerian contained relatively high benzo[a]pyrene levels. On average, PAH4 intake resulting from food supplement use will be at the lower end of the range of contributions of main food groups to PAH4 exposure, although individual food supplements can contribute significantly to PAH4 exposure. Regular control of EFSA indicator PAH levels in food supplements may prove a way forward to reduce further the intake of PAH from food.
Assuntos
Suplementos Nutricionais/análise , Contaminação de Alimentos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Animais , Benzo(a)pireno/análise , Benzo(a)pireno/toxicidade , Carcinógenos/análise , Carcinógenos/toxicidade , Suplementos Nutricionais/toxicidade , Ingestão de Alimentos , Inocuidade dos Alimentos , Humanos , Mutagênicos/análise , Mutagênicos/toxicidade , Países Baixos , Plantas Comestíveis/química , Plantas Comestíveis/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidadeRESUMO
BACKGROUND: The impaired glucose tolerance (IGT) state is characterized by insulin resistance. Disturbances in fatty acid (FA) metabolism may underlie this reduced insulin sensitivity. The aim of this study was to investigate whether the prediabetic state is accompanied by changes in the expression of genes involved in FA handling during fasting and in insulin-mediated conditions and to study the impact of weight loss. METHODS: Seven IGT men and 5 men with normal glucose tolerance (NGT), comparable in terms of age and BMI, participated in the study. The 5 IGT men followed a 12-week weight loss program. Muscle biopsies were taken and the expression of 6 genes was investigated. RESULTS: Subjects had a reduction of 15.5 ± 4.3 kg in body weight. Baseline gene expression was not different between NGT and IGT men. After a hyperinsulinemic clamp, there was an overall upregulation of PGC1α, SREBP-1c, SREBP-2, and ACC-2. The upregulation of SREBP-2 was more pronounced in IGT men (p = 0.049). Weight loss significantly increased insulin sensitivity by 71%, which was not reflected in altered gene expression profiles. CONCLUSIONS: SREBP-2 shows altered insulin responsiveness in IGT men compared with NGT men, while there were no differences in basal gene expression.
Assuntos
Ácidos Graxos/metabolismo , Regulação da Expressão Gênica , Intolerância à Glucose/genética , Intolerância à Glucose/metabolismo , Metabolismo dos Lipídeos , Índice de Massa Corporal , Primers do DNA , Técnica Clamp de Glucose , Humanos , Masculino , Pessoa de Meia-Idade , Músculo Esquelético/metabolismo , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Redução de PesoRESUMO
Traditional herbal preparations used in Ayurveda, traditional Chinese medicine, traditional Tibetan medicine, and other Asian traditional medicine systems may contain significant amounts of mercury, arsenic or lead. Though deliberately incorporated in Asian traditional herbal preparations for therapeutic purposes, these constituents have caused intoxications worldwide. The aim of this study was therefore to determine mercury, arsenic, and lead levels in Asian traditional herbal preparations on the Dutch market. A total of 292 traditional herbal preparations used in Ayurveda, traditional Chinese medicine, and traditional Tibetan medicine were sampled between 2004 and 2007. Samples were mostly multi-ingredient traditional herbal preparations containing herbs and minerals. The labeling of less than 20% of the traditional herbal preparations suggested the presence of mercury, arsenic or lead. These elements were shown by inductively coupled mass spectrometry (ICP-MS) in 186 (64%) of 292 traditional herbal preparations. Estimated weekly mercury, arsenic, and lead intake levels were calculated for each traditional herbal preparation from the analytically determined concentrations and the recommended dose. A total of 59 traditional herbal preparations (20%) were likely to result in intakes of these elements significantly exceeding safety limits. Of these 59 traditional herbal preparations, intake estimates for 50 traditional herbal preparations significantly exceeded the safety limit for mercury (range = 1.4-1747 mg week(-1)); intake estimates for 26 traditional herbal preparations significantly exceeded the safety limit for arsenic (range = 0.53-427 mg week(-1)) and intake estimates for eight traditional herbal preparations were significantly above the safety limit for lead (range = 2.6-192 mg week(-1)). It is concluded that the mercury, arsenic, and lead contents of traditional herbal preparations used in Ayurveda, traditional Chinese medicine, and traditional Tibetan medicine remain a cause for concern and require strict control.
Assuntos
Arsênio/análise , Chumbo/análise , Ayurveda , Medicina Tradicional Chinesa , Mercúrio/análise , Limite de Detecção , Espectrometria de Massas , Países Baixos , Medição de RiscoRESUMO
BACKGROUND/OBJECTIVES: Acrylamide, a probable human carcinogen, was detected in various heat-treated foods such as French fries and potato crisps. Recently, positive associations have been found between dietary acrylamide intakes, as estimated with a food frequency questionnaire using an acrylamide database, and cancer risk in some epidemiological studies. As acrylamide levels vary considerably within the same type of foods, a validation study was performed to investigate whether use of an acrylamide food database containing calculated mean acrylamide content, based on extensive sampling and chemical analysis of Dutch foods (several samples per food), can classify subjects with respect to true acrylamide intake. SUBJECTS/METHODS: We used the data from a 24-h duplicate diet study. The acrylamide content of 39 Dutch 24-h duplicate diets collected in 2004 was estimated using the mean acrylamide levels of foods available from the database and the menu list, on which the participants of the duplicate diet study had listed the amounts of individual foods and drinks in household units. Next, the acrylamide content of the total duplicate diets was analytically measured and correlated to the estimated acrylamide contents. RESULTS: The Spearman's correlation coefficient between chemically determined acrylamide content and the calculated acrylamide content of the duplicate diets was 0.82 (P<0.001). CONCLUSIONS: This study indicates that it is possible to classify subjects with respect to acrylamide intake if mean instead of actual content of each food is applied. The database can therefore be applied in epidemiological studies on acrylamide intake and cancer risk, such as the Netherlands Cohort Study on Diet and Cancer.
Assuntos
Acrilamida/análise , Carcinógenos/análise , Bases de Dados Factuais , Dieta/classificação , Estudos Epidemiológicos , Análise de Alimentos , Acrilamida/administração & dosagem , Adolescente , Adulto , Idoso , Carcinógenos/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/epidemiologia , Países Baixos , Estatísticas não Paramétricas , Adulto JovemAssuntos
Infecções por HIV/epidemiologia , Feminino , Humanos , Incidência , Masculino , Comportamento Sexual , Uganda/epidemiologiaRESUMO
In March 2006, a joint workshop was organized by the European Commission and the Confederation of EU Food and Drink Industries (CIAA) to discuss current knowledge and achievements in the reduction of acrylamide levels. This paper focuses on the progress made with cereal products. At present, the reduction options available are applicable to a limited number of cereal products and are product-specific. The following are the most promising: * Adjustment of time and temperature during baking. * Extend fermentation times where feasible. * Substitution of ammonium bicarbonate with alternatives where feasible. * Avoid or minimise use of reducing sugars where possible. * Maintenance of uniform control of the colour and avoidance of very high baking temperature where possible. The most promising near-term technical solution is the use of asparaginase. This enzyme has the potential to achieve a 60-90% reduction for some products made from dough or batter, which can be held for a time. In the longer term, the optimisation of agronomy and plant breeding for wheat has the potential to reduce acrylamide in all foods on any scale, whether domestic or industrial. Importantly, nutritional and toxicological issues, other than acrylamide, must also be considered so as to ensure that the steps taken to reduce acrylamide levels do not have other adverse effects on diet.
Assuntos
Acrilamida/análise , Carcinógenos Ambientais/análise , Grão Comestível/química , Contaminação de Alimentos/análise , Asparaginase/metabolismo , Asparagina/análise , Pão/análise , Culinária/métodos , Fermentação , Contaminação de Alimentos/prevenção & controle , Manipulação de Alimentos/métodos , Avaliação Nutricional , Medição de Risco/métodosRESUMO
OBJECTIVES: This study is part of a continuous evaluation of the Swiss AIDS prevention strategy from 1987 through 1994. METHODS: Annual telephone surveys of samples representative of the general population aged 17 through 45 years have been conducted since 1987 to monitor behavioral change. RESULTS: No major changes in level of sexual activity (lifetime number of partners, frequency of sexual encounters in the past week) or potential exposure to risk of HIV transmission (acquisition of a new steady partner during the year or of casual partners in the last 6 months) were observed. Systematic condom use with a new steady partner increased between 1988 and 1994, from 40% to 64% among 17- to 30-year-olds and from 57% to 72% among those aged 31 to 45. Systematic condom use with casual partners increased from 8% to 56% between 1987 and 1994 among 17- to 30-year-olds and from 22% to 42% between 1989 and 1994 among those aged 31 to 45. Condom use was higher among those with multiple partners. CONCLUSIONS: A general-population approach to AIDS prevention was able to achieve large-scale improvements in condom-based protection against HIV infection without inducing other major changes in sexual behavior.
Assuntos
Síndrome da Imunodeficiência Adquirida/prevenção & controle , Preservativos/estatística & dados numéricos , Comportamento Sexual , Adolescente , Adulto , Métodos Epidemiológicos , Medo , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Pessoa de Meia-Idade , Distribuição Aleatória , Estudos de Amostragem , Inquéritos e Questionários , Suíça , TelefoneRESUMO
This paper examines the transmission dynamics of human immune deficiency virus type 1 (HIV-1) in the male homosexual population in the U.K. via numerical studies employing a mathematical model representing the principal epidemiological process. The model is based on an assumption of proportionate mixing between different sexual-activity classes (defined by the rate of sexual partner change per unit of time) and incorporates heterogeneity in sexual activity, distributed infection and incubation periods and the recruitment of susceptibles to the sexually active population. The sensitivity of model predictions to various assumptions and parameter assignments is examined. Numerical studies of model behaviour focus on the influence of changes in the magnitudes of the transmission parameters, associated with three periods of infectiousness during the incubation period of acquired immune deficiency syndrome (AIDS), on the magnitude and duration of the epidemic and on the level of the endemic equilibrium state. Predicted temporal trends in the incidence of AIDS are shown to be particularly sensitive to changes in the intensities and durations of the stages of infectiousness. Most of the paper addresses the influence of changes in sexual behaviour on the magnitude and duration of the epidemic. Numerical simulations show that the manner in which behavioural changes occur and who is influenced by such changes (i.e. infecteds or susceptibles, the sexually active population or new recruits to this population) have a major impact on the future timecourse of the epidemic. The greatest reduction in the incidence of AIDS over the coming decades is induced by changes in the rate of sexual-partner change among the sexually active population, particularly those currently infected. The time periods at which changes in behaviour occur, in relation to the starting point of the epidemic (assumed to be 1979), are also of particular significance to the future pattern of the incidence of disease and infection. Changes in behaviour early on in the timecourse of the epidemic have a much greater impact than equivalent changes at latter time points. On the basis of limited data on the pattern of change in sexual behaviour among the male homosexual community in the U.K., numerical studies of model behaviour tentatively suggest that the epidemic is at, or near to, a period of peak incidence of the disease AIDS. Analyses suggest that, following the peak in incidence, there will be a period of slow decline over many decades provided recent changes in behaviour are maintained in the coming years.(ABSTRACT TRUNCATED AT 400 WORDS)